In telecommunications, presence information indicates the ability, availability and willingness of a person to communicate. A person's presence information provides contextual information to help others decide if they should try to contact the user and which mode of communication would be most appropriate at that time.
Presence is currently one of the key drivers behind instant messaging (IM) and some of the recent developments in VoIP technology, in particular Session Initiation Protocol (SIP). While these and other rudimentary presence technologies have been implemented and discussed (see, e.g., the IETF's RFC 2778 entitled “A Model for Presence and Instant Messaging” and RFC 4480 entitled “RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF)”), these technologies are still generally quite embryonic. These prior-art technologies provide limited flexibility, scalability, security and privacy. Accordingly, improvements in the manner in which presence information is collected, managed and disseminated remain highly desirable. Techniques that improve the ease and efficiency with which devices may register and interact with the presence system also remain highly desirable.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.